I've been playing this mod for a couple of hours straight and I have to say... WOW! This is incredible, in some respects its a lot better than the original game. I dunno what the others are talking about with regards to "lag", I'm running the advanced graphics at 1680x1050 and there is no lag at all plus it looks great (granted there are a few bugs).

The level design is great, characters great and story has got me hooked already. The combat... holy crap its freakin amazing, the guns look and sound amazing; its so satisfying to drop some thugs with bursts from the mp5.